Valutazione della capacità di rientro alla base di un elicottero in presenza di danno balistico ad un albero di trasmissione della linea rotore di coda

Nella progettazione di un elicottero militare, destinato ad operare a bassa quota e in ambiente ostile, il danneggiamento di componenti critici, conseguente ad impatto balistico, riveste un ruolo primario nella valutazione delle possibilità di sopravvivenza dell’intera macchina. In questo articolo è quindi proposto uno studio sperimentale, suddiviso in diverse fasi, riguardante la verifica della capacità di un elicottero di portare a termine una missione di rientro alla base a potenza ridotta e in presenza di danneggiamento balistico ad un albero di trasmissione della linea rotore di coda. Il lavoro ha richiesto dapprima l’esecuzione, su esemplari del componente in esame, di prove sperimentali di impatto balistico, condotte utilizzando un proiettile calibro 7.62 NATO. Successivamente su ciascun albero danneggiato sono state eseguite prove torsionali statiche ed a fatica, il cui scopo è stato verificare la resistenza residua del componente all’applicazione di opportuni carichi rappresentativi delle sollecitazioni riscontrate durante la missione di rientro

An interview with Howard Gardner: John H. and Elisabeth A. Hobbs research professor of cognition and education at the Harvard Graduate School of Education

The present interview was realized for the occasion of the panel on “Educating to Scientific Thinking” at the sixth Edition of the General States of Digital School in Bergamo (Italy, 2021). The interview focuses on six topics reflecting on scientific thinking, the forms of creativity and the many intelligences that it hinges on. Introduced by observations on the educational system, each question is asked in the light of the ideas developed in “A Synthesizing Mind”, as well as in “Frames of Mind”, “The Good Project”, and “Five Minds for Future”. From the conversation, a consistent picture emerges, which is in fact continuously evolving while artificial intelligence and quantum technologies pervade our everyday lives, and fundamental research questions about the human mind gain the center of the stage

Valutazione della capacità di rientro alla base di un elicottero in presenza di danno balistico ad un albero di trasmissione della linea rotore di coda

Nella progettazione di un elicottero militare, destinato ad operare a bassa quota e in ambienteostile, il danneggiamento di componenti critici, conseguente ad impatto balistico, riveste un ruolo primario nellavalutazione delle possibilità di sopravvivenza dell’intera macchina. In questo articolo è quindi proposto unostudio sperimentale, suddiviso in diverse fasi, riguardante la verifica della capacità di un elicottero di portare atermine una missione di rientro alla base a potenza ridotta e in presenza di danneggiamento balistico ad unalbero di trasmissione della linea rotore di coda.Il lavoro ha richiesto dapprima l’esecuzione, su esemplari del componente in esame, di prove sperimentali diimpatto balistico, condotte utilizzando un proiettile calibro 7.62 NATO. Successivamente su ciascun alberodanneggiato sono state eseguite prove torsionali statiche ed a fatica, il cui scopo è stato verificare la resistenzaresidua del componente all’applicazione di opportuni carichi rappresentativi delle sollecitazioni riscontratedurante la missione di rientro

Improving Bowen-ratio estimates of evaporation using a rejection criterion and multiple-point statistics

The application of the Bowen ratio method to estimate evaporation is heavily affected by uncertainties on the measured quantities. Time series collected with a hydro-meteorological monitoring station often contain measurements for which a reliable estimate of evaporation cannot be computed. Such measurements can be identified with standard error propagation methods. However, simply discarding some values might introduce a bias in the cumulative evaporation for long time intervals, also depending on the threshold of acceptance. In this paper, we propose the use of multiple-point statistics simulation to integrate the time series of reliable evaporation estimates. A test conducted on a two-year-long time series of data collected with a hydro-meteorological station in the Po plain (Italy) shows that the usage of a rejection criteria in conjunction with multiple-point statistics simulation is a promising and useful tool for the reconstruction of reliable evaporation time series. In particular, it is shown that if the rejected values are not replaced by simulation, then the cumulative evaporation curves are estimated with a bias comparable with estimates of cumulative annual evaporation. Moreover, the test gives some insights for the selection of the best rejection threshold

A quasi three dimensional model of water flow in the subsurface of Milano (Italy): the stationary flow

International audienceA quasi three-dimensional model is developed to simulate the behaviour of the aquifer system which is the resource of drinkable water for the town of Milano (Italy). Non continuous semipermeable layers locally separate permeable levels in a multilayered system, consisting of a phreatic and three confined aquifers. The numerical model is a conservative finite difference scheme based on the discretisation of the water balance equation for stationary flow. The grid spacing is 500 m and has been chosen, taking into account the distribution of the data in an area of about 400 km2. The model has been calibrated with a "trial and error" procedure, by comparison of the results of the model with the observations for three years (1950, 1974 and 1982) which correspond to different flow situations. Once calibrated, the model has been used as a predictive tool, to forecast the behaviour of the aquifer system for other years of the 20th century; the comparison between the model forecasts and observations is good. The model is capable of describing both the strong drawdown of the water table in the 1970s, when the water demand for domestic and industrial needs was very high, and the rise of the water table in the 1990s, when water extraction decreased. The results of the model confirm that the phreatic level is controlled largely by the local extraction of water; moreover, the aquifer system reacts to an increasing water demand with a small increase of the inflow and with a strong decrease of the outflow from its boundaries

Magnetostructural transition and magnetocaloric effect in Ni55Mn20Ga25 single crystals

A first order transition from a paramagnetic-austenite phase to a ferromagnetic-martensite phase occurring in off-stoichiometry single crystals of Ni2MnGa at 313 K presents unique features due to the multifunctional character of the magnetic shape memory alloy. A remarkable magnetocaloric effect, associated with an entropy change up to ΔS≈−86 J kg−1 K−1 and an adiabatic temperature change ΔT≈2.2 K, accompanied by mechanical strain Δε⩾3% have been observed in samples subjected to changes of the applied magnetic field ΔH=4×106 A∕m (≈5 T). The effects of magnetic field, temperature, and stress on the entropy variationΔS are quantified and compared

Homogeneity of Interspecific Hybrids Between Saccharomyces cerevisiae and Saccharomyces uvarum by Phenotypic and Transcriptional Analysis

Oenological traits, such as temperature profile and production of certain metabolites, were tested for four interspecifc hybrids obtained by"spore to spore" crossing between Saccharomyces cerevisiae and Saccharomyces uvarum strains and uniformity of their inheritance was found. PCR/RFLP analysis of ITS regions was carried out to confirm the hybrid nature of the strains. They showed an additive profile with five bands of the respective 325, 230, 170 and 125 bp. Finally gene expression study was performed by comparative DNA macroarray analysis of the hybrids and the preliminary results showed that the global gene expression patterns of hybrids are remarkably similar to one another. In conclusion, the data obtained by two different approaches, such as metabolic and transcriptomic strategies, suggest a large degree of homogeneity among interspecific hybrids between S. cerevisiae and S. uvarum. Moreover, the uniformity of F1 hybrids advises that the oenological trait inheritance mechanism is highly constant and reproducible